1. Field of the Invention
The present invention relates to a method of managing defects in a hard disk drive, and more particularly, to a method of managing defects in a hard disk drive in a case where the position of defects on a disk is known in advance, a recording medium therefor, and a hard disk drive therefor.
2. Description of the Related Art
A head in a hard disk drive is movable using a stepping motor or a voice coil motor. The stepping motor is mainly used in a floppy disk drive. In this case, the head is moved via a drive shaft which steps a precise distance. On the other hand, in the case of using a voice coil motor, the head is moved in response to a specific signal written on a disk, such as a servo signal.
In the case of a hard disk drive, one section (platter) of a disk is used for the servo signal and an additional head for reading the servo signal is provided in the hard disk drive. This method is used only for reading the servo signal.
In an embedded servo method which is more commonly used, a servo signal is written on a track of a disk so that all platters on the hard disk drive are useable for data storage. Thus, a head in the embedded servo method can read the servo signal as well as data.
In the method using the voice coil motor, the head is more correctly accessed than in the method using the stepping motor, and an access time is shortened. In particular, in a case of the embedded servo method, the correction of an off-track is performed in real-time, and a disk is useable in many fields.
In the case of the embedded servo method, the servo signal is written on the disk using a servo write process in a hard disk drive manufacturing process. The servo signal is written on the disk using equipment such as a servo writer, or by self servo writing.
In a conventional hard disc drive, a servo signal is written on a disk by moving a head either from an outer diameter (OD) to an inner diameter (ID) of the disk or from an ID to an OD of the disk, that is, in a single direction. Recently, a method of writing a servo signal in a direction in which the writing direction of the servo signal varies in a middle area (an area where a skew angle is 0) of the disk, i.e., a method of writing a servo signal bidirectionally, taking an effect caused by a skew angle into account, has been used.
However, in the method of writing a servo signal bidirectionally, due to limitations such as the accuracy of a servo writer, the portion where the skew angle is 0 is not correctly recognized. Thus, an area (hereinafter, referred to as an alternate write area) where the servo signal is alternately written on a disk inevitably occurs in the vicinity of a place where the writing direction of the servo signal is reversed. Servo data may be abnormally written in the alternate write area.
To solve this problem, in a conventional method of managing defects in a hard disk drive, a data zone is divided centering on a track where the writing direction of the servo signal is reversed, and an alternate write area is divided and allocated to adjacent data zones, and an area corresponding to the alternate write area in an area in the data zone is managed for track defects.
In the above-described method, the alternate write area must be checked during a process of inspecting defects in a hard disk drive manufacturing process, and since a large amount of time is required for defect inspection, the hard disk drive production rate is reduced.
In addition, in one data zone adjacent to the alternate write area, part of the alternate write area is allocated to a spare area, and the spare area is managed for defects. Thus, a capacity of managing defects in the data zone is reduced as much as the defect-managed spare area. In another data zone adjacent to the alternate write area, part of the alternate write area is allocated to a data area, and the data area is managed for defects. Thus, the capacity of the data zone is reduced as much as the defect-managed data area. Further, as the recording density of a disk increases, the number of track defects to be managed for defects increases. Thus, these problems cannot be solved by using an existing spare area.